ANTIGRAVITY CLI DEEP DIVE: GOOGLE'S FREE AI CODING AGENT IN 2026

• 18/6/2026
• 8-minute read
• 1547 words

Google’s terminal AI agent has been through a name change, model upgrades, and a strategy shift — but one thing hasn’t changed: it remains the best free option in the market. Antigravity CLI (the tool you may still know as Gemini CLI) gives you a 1M token context window, Google Search grounding, and multimodal input, all without a credit card.

Who Is This Guide For?

This is for developers who want a free, capable AI coding agent without committing to a paid subscription, engineers evaluating Antigravity CLI against Claude Code or Codex CLI, teams that benefit from Google Search grounding for debugging, and anyone curious about what the Gemini→Antigravity rebrand actually means.

By the end of this, you’ll know exactly what Antigravity CLI offers on the free tier, how the Gemini 3 models perform on real coding tasks, what the rebrand from Gemini CLI means for the tool’s future, how Antigravity compares to paid alternatives, and whether it’s sufficient as your primary AI coding agent or best used as a complementary tool.

For the full landscape of all 11 CLI agents including Claude Code, Codex CLI, OpenCode, and Aider, see the master comparison .

The Rebrand: Gemini CLI → Antigravity CLI

In mid-2026, Google renamed Gemini CLI to Antigravity CLI and moved from an npm-distributed tool to a native binary. The old @google/gemini-cli npm package still exists for legacy users, but new installs use platform-native scripts. The name change signals Google’s intent to make the CLI model-agnostic: future versions may support non-Gemini models.

For developers using the tool today, the old npx @google/gemini-cli path still works for those with existing installs, but new installs should use the native binary approach below.

What You Get for Free

The free tier exists — but it comes with aggressive rate limiting that makes serious coding work difficult without a paid plan.

Free tier reality:

• Burst limit: 60 requests per minute (the headline number Google advertises)
• Daily cap: Effectively ~20-50 complex coding tasks before hitting the shared quota
• Weekly cap: A combined rate limit across all models (Flash + Pro were merged into one pool in May 2026)
• 5-hour refresh cycle: Quota partially refreshes every 5 hours — not instantly
• One complex task can consume the equivalent of 50-100 standard chat prompts, burning through the weekly limit fast

Google advertises “60 requests per minute” but the practical constraint is the combined weekly quota shared across all Antigravity models. One heavy debugging session can max it out. The free tier is a trial — useful for experimentation but not a daily driver for professional coding work. Source: Google Antigravity plan changes , XDA review

For context: Claude Code’s cheapest reliable access is $100-200/month (Max plan). Codex CLI requires ChatGPT Plus at $20/month. Antigravity CLI at $0 lets you try the tool — but if you find yourself hitting “baseline model quota reached” every afternoon, a Pro subscription or move to a different agent is inevitable.

Installation:

# macOS / Linux (native binary)
curl -fsSL https://antigravity.google/install.sh | bash

# Linux (apt)
sudo apt install antigravity

Source: Antigravity CLI documentation

Authenticate with a personal Google account (OAuth), a Gemini API key, or Vertex AI credentials. The OAuth flow is the simplest — sign in with Google, and you’re coding.

Gemini 3: What the Model Can Actually Do

Gemini 3 is Google’s latest generation model, and it powers the Antigravity CLI experience. On coding benchmarks, the numbers tell a consistent story:

The SWE-bench gap is real — Gemini 3 trails both Opus 4.8 and GPT-5.5 on raw code-fixing ability. But benchmarks don’t capture what Antigravity CLI does uniquely well: combining code understanding with live web search.

Gemini 3 + Google Search grounding means Antigravity can debug an obscure library error by searching the web for recent GitHub issues, Stack Overflow answers, and documentation changes — all within the same agent session. Claude Code and Codex CLI can’t do this. For debugging novel errors in fast-moving ecosystems (JavaScript frameworks, CI/CD tooling, cloud SDKs), this is a genuine advantage.

Features That Set Antigravity Apart

Google Search grounding. This is Antigravity’s killer feature and the one no other CLI agent matches. When you hit an error, Antigravity doesn’t just read your code — it searches the web for solutions. This is especially powerful for:

• Debugging npm/pip dependency conflicts where the fix was posted yesterday
• Verifying library API compatibility before writing code
• Finding configuration patterns for new cloud services
• Researching security vulnerabilities in real-time

Multimodal input. Drop a PDF, screenshot, or hand-drawn architecture diagram into the chat. Antigravity processes images natively. Need to build an API from a Swagger screenshot? Antigravity reads the image and generates the code.

GEMINI.md files. Project-level context files that customize agent behavior — think .cursorrules or CLAUDE.md, but for Google’s agent. Define your project conventions, preferred libraries, and coding standards in a single file.

GitHub Action integration. The official GitHub Action enables automated PR reviews, issue triage, and on-demand help by mentioning @gemini-cli in comments. For teams already on GitHub, this is zero-config CI/CD AI.

MCP extensibility. Connect Antigravity to Model Context Protocol servers for media generation (Imagen, Veo, Lyria), database access, or custom tool integrations. The MCP ecosystem is growing, and Antigravity participates fully.

Conversation checkpointing. Save and resume complex sessions across days. Essential for multi-day refactoring projects where losing context means starting over.

Where Antigravity Falls Short

Raw intelligence. Let’s be direct: at 63.8% SWE-bench, Gemini 3 is substantially behind Claude Opus 4.8 (88.6%) and GPT-5.5 (82.1%) on pure code-fixing ability. If your primary workflow is autonomous debugging of complex bugs, Antigravity will solve fewer of them than Claude Code or Codex CLI.

Agent sophistication. Antigravity’s agent harness is simpler than Claude Code’s. No nested sub-agents, no hooks system, no plugins ecosystem, no checkpoints. It’s a straightforward chat agent with tool use — competent, but not sophisticated.

Search grounding tradeoff. The web search that makes Antigravity unique can also be a liability. For highly specialized internal codebases with no public documentation, Antigravity sometimes reaches for the web when local repository context would be more relevant. You’ll need to guide it with explicit prompts when working on proprietary code.

Aggressive rate limiting. This is the real catch. Google merged Flash and Pro model rate limits into a single shared pool in May 2026, meaning all your Antigravity usage draws from one quota. Complex coding tasks consume quota disproportionately — one architecture review can use as much as 20 quick chat questions. The “baseline model quota reached” error is a frequent complaint across Reddit and Google’s own support forums. For serious daily coding, you’ll likely need a paid tier or a different agent.

Antigravity CLI vs. The Paid Options

Antigravity CLI’s free tier is a real free tier — no credit card, instant access. But it’s structured as a trial, not a sustainable daily driver. The combined quota system introduced in May 2026 makes heavy coding sessions hit the wall fast. For evaluating whether CLI AI agents are for you, it’s perfect. For replacing Claude Code or Codex CLI as your primary agent, it’s not there yet.

When Antigravity CLI Is the Right Choice

• You’re evaluating whether CLI AI agents are worth adopting — zero commitment to try
• You need web-grounded debugging for obscure errors in fast-moving ecosystems
• You work with multimodal inputs (screenshots, PDFs, diagrams) and want native support
• You’re a student, open-source contributor, or hobbyist with light coding needs
• You already use a paid agent and want a free complementary tool for specific tasks
• You need a free CI/CD agent for occasional automated PR reviews (not heavy pipelines)

When to Use Something Else

• You hit “baseline model quota reached” more than once a week → time for a paid agent
• You’re debugging complex, multi-file production bugs → use Claude Code + Opus 4.8
• You want maximum speed and pipeline-friendly output → use Codex CLI + GPT-5.5
• You need Git-native, reviewable edits with no rate limit anxiety → use Aider
• You’re designing system architecture → use Goose

For a detailed comparison of Claude Code vs Codex CLI, see the head-to-head deep dive . For the complete open-source agent landscape, see OpenCode, Aider, Goose, and Pi .

What You Can Actually Use Today

# Install Antigravity CLI (native binary):
curl -fsSL https://antigravity.google/install.sh | bash

# Or on Linux:
sudo apt install antigravity

# Authenticate with Google (no credit card)
# You now have access to:
# - Gemini 3 model
# - 1M token context window
# - Google Search grounding
# - Multimodal input
# - MCP extensibility

For the full landscape of all 11 CLI coding agents including benchmarks, pricing, and cost-per-intelligence analysis, see the master comparison .